In some examples, in response to a reset of an electronic device, a method disables hardware write locking of a first region in a non-volatile memory, and executes a first boot code portion from the first region to begin a boot procedure. The executed first boot code portion checks whether an update code for the first boot code portion exists. In response to determining that no update code for the first boot code portion exists, the executed first boot code portion causes hardware write locking of the first region. After causing the hardware write locking of the first region, the boot procedure continues, the boot procedure comprising verifying an integrity of a second boot code portion.